Generally, an antenna structure for an antenna system is selected depending on a performance, a cost, and an environment thereof. That is, the antenna structure must be selected in order to develop a low cost antenna that satisfies a high gain antenna characteristic in a high frequency band and a multi-band which are a communication environment between a satellite and a mobile object.
A conventional antenna system includes a mechanical antenna system and a phased array antenna system.
The mechanical antenna system is mainly used for long distance satellite communication for providing a fixed antenna beam. Especially, the mechanical antenna system is widely used as a low gain single or dual band mobile antenna system because the cost of the mechanical antenna system is affordable. Also, the mechanical antenna system is used as a small antenna having a wide antenna beam using a mechanical tracking scheme in the mobile environment.
The phased array antenna system is mainly used as a military antenna (radar) for accurately and finely tracking a target object because the phased array antenna system is capable of tracking a target object in high speed using an electric beam.
However, the conventional antenna system has following shortcomings.
The mechanical antenna system becomes incapable of tracking a satellite when the antenna beam becomes narrower, for example, narrower than 1.0°, due to the increment of a gain.
Also, a phased array antenna system satisfying a multi-band, a high frequency, a high gain, and a wide beam scan sector is very expensive, and such a phased array antenna system has limitations to embody.
Therefore, there is a demand for developing an antenna system having the advantages of the conventional antenna system, such as a mechanical antenna system and a phased array antenna, with the optimal economical efficiency.